noun
miniature light bulb; midget lamp
Abbreviation of 豆電球 (まめでんきゅう). Used in contexts such as electronics, science experiments, and small indicator lights.
See also: 豆電球
豆球が切れたので交換した。
The miniature bulb burned out, so I replaced it.
理科の実験で豆球を使った。
We used a miniature light bulb in the science experiment.